Drifting plate capacitor setting for homebrew amp

[K5UJ]

I've been driving pr 3-500zg with about 20 w. for ~330 ma Ip @ ~2.8 KV for approximately 300 w. out* into a Bird 1.5 KW d.l.  I move a lot of air through the RF deck and plate supply--180 CFM and the chinese graphite anodes get bright orange and stay that way while I blather for 10+ minutes in one of my weekend afternoon "yacking over the back fence" QSOs.   Air cooling volume is key and makes the difference between what you can do with the amp on AM and what you can't.  Avoid doorknobs in the amp's output tank circuit as loading padders; I learned that the hard way--they don't like lots of AM duty cycle buzzard transmission 160 m. current   

*Power measurements not precise but limited to the Bird 43 5% error spec.

Rob

[WA5VGO]

If those green wires under the tube sockets are grid returns (and I'm pretty sure they are) I would consider shortening them. In fact, there are generally slots in the side of the socket that will allow you to slip a strap into it and solder it directly to the socket. Short, low inductance leads will make a big difference in the stability of the amplifier.

73,
Darrell, WA5VGO

[Steve - K4HX]

I've been running 2x3-500Z exactly that way since 1997. It works.

Thats 100W PEP which will easly draw 800ma on voice peaks. If I drive the LK-500 at 30-35W the tubes really glow plus they are into splatter mode. And thats with only 2600V key down.

At 3000V and 400ma of carrier thats 800W doing nothing but helping the anode glow, there isnt much headroom left especially without a forced air chimney cooling system.

[W2VW]

I've been running 2x3-500Z exactly that way since 1997.

That's a really long transmission.

[K1JJ]

That's a really long transmission.

There's a certain individual in Belgrade Lakes, ME who might be very interested in this technology.

[W2VW]

That reminds me. I have a few dead transformers I'd like to drop off there....from about 10,000 feet.

That's a really long transmission.

There's a certain individual in Belgrade Lakes, ME who might be very interested in this technology.

[K1JJ]

Falling transformers have mass, gravity and relativity too. Did you submit your paper for the 2011 Physics Colloquium coming up in August?

[W2VW]

No. I was previously disqualified for attempting to violate the laws of physics.

Falling transformers have mass, gravity and relativity too. Did you submit your paper for the 2011 Physics Colloquium coming up in August?